1. Field of the Invention
The present invention concerns a device for adjustment of the focus position of the therapy head of a lithotripsy system.
2. Description of the Prior Art
Adjustment of the position of the focus of the therapy head of a lithotripsy system can be accomplished using an x-ray system, usually in the form of a C-arm x-ray system. The x-ray system, having an x-ray source and an image intensifier, serves for imaging during a kidney stone treatment. For adjustment of (setting) the shockwave focus onto a central point detectable by the x-ray system from different angles, a target marking on the image intensifier of the x-ray system is necessary in the case of such a C-arm. This is the isocenter. A device serving for this purpose is a cross-hair disc that is affixed on the image intensifier with a fastening device. The target marking furthermore serves for positioning the shockwave focus in a stone to be treated. Such a cross-hair disc is formed of a material permeable to x-rays. A target or cross-hair made from a material that can be imaged in the image intensifier is disposed in its center. In the case of lithotripsy systems with an integrated x-ray system, the image intensifier is already provided at the factory with a cross-hair disc that is attached on the image intensifier such that cross-hair disc cannot be adjusted. To accommodate users undertaking only a small number of stone treatments, in more recent times the fixed mechanical coupling between the x-ray systems and the lithotripsy systems has been abandoned, particularly for cost reasons. Mobile lithotripsy systems are used that can be assigned to an arbitrary x-ray system via a mechanical interface. This allows the use of existing x-ray systems, used for other purposes, for lithotripsy as well. A problem, however, is the cross-hair disc is missing on the image intensifier, because the x-ray system is used otherwise.